Production of new vat dyestuffs



25 vat dyestuffs of excellent fastness.

Patented Jan. 7, 1930 UNITED STATES;

PATENT I OFFICE PAUL rmwmsxx, or LUDWIGSHAFEN-ON-THE-RHINE, AND JULIUS MULLER, on

MANNHEIM, GERMANY, ASSIGNORS T GENERAL ANILINE WORKS, INC., OF NEW YORK, N. Y., A CORPORATION OF DELAWARE PRODUCTION OF NEW VAT DYESTUFFS No Drawing. Application filed September 22, 1927, Serial No. 221,396, and in Germany September 22, 1926.

We have found that valuable new vat dyestufis are produced by treating with alkaline agents the aminobenzanthrone obtainable by reducing the nitrobenzanthrone described in Example 2 of the U. S. Patent'No. 876,679. If, for example,the said aminobenzanthrone be fused with alcoholic potash, a brilliant green dyestufi' is obtained. Other vat dyestuffs may be obtained by employing other alkaline agents or varying the conditions with regard to proportions, temperature and the like.

Similar valuable vat dyestufl's, which are often identical with the green dyestuif just described are obtained by treating substitution products of the aforesaid aminobenzanthrone, which contain exchangeable substituents in the Bz-l-position, or the N-acylated derivatives thereof with alkaline agents. The temperature employed for the treatment with alkaline agents will generally range between about 120 and 200 C.

The green dyestuffs prepared according to the methods above described are transformed by the action of oxidizing agents into brown ThebroWn dysestu'fi's may alsobe produced on the fibre, by

treating the dyeings made with the said green dyestuifs with oxidizing agents such as hypochloribes, fast brown dyeings being produced.

Similar brown vat dyestuffs are also obtained in a simple manner by treating the beforementioned nitrobenzanthrone directly with alkaline agents. The resulting dyestuffs may be purified by treatment with oxidizing agents such as hypochlorite.

v The followin examples will serve to further illustrate t e nature of the said invention but the invention is not limited to these examples. The parts are by weight.

Ewample l 10 parts of ethyl alcohol to 150 (3., the excess, 5 of alcohol being distilled 01f. To this melt are added, at 140 to 150 C., 2 parts of the aminobenzanthrone, prepared by reducing the nitrobenzanthrone described in Example 2 of the said U. S. Patent No. 876,679 and corresponding probably tothe formula:

This temperature is maintained until the formation of the dyestufi is complete. The melt is then stirred into water, boiled up, and the resulting dyestuff is separated out by blowing in air, after which it is filtered off by suction, Washed with water and dried. It gives strong green dyeings on cotton from a bluish-green vat. The solution of the dyestufl' in concentrated sulfuric acid is violet with a reddish tinge. The reaction proceeds probably in accordance with the following equation, but 1t should be noted that the dyestuif is first obtained in the form of its hydro compound:

Example 2 3 parts of the aminobenzanthrone used in Example 1 are introduced into 15 parts of fused potassium hydroxid at 200 0., the temperature being then raised to 270 to 280 C. for minutes, with stirring. After cooling, the melt is poured into water, then warmed for a short time, and the dyestufi separated by blowing in air. After being worked up in the usual way, the dyestuif gives grey dyelngs on cotton from a blue vat. It dissolves in concentrated sulfuric acid to a violet solution with a reddish tinge. The constitution of the dyestuff is not known.

Example 3 5 parts of the dyestufi, obtained according to Example 1, are brought intoa state of fine distribution and suspended in glacial acetic acid. A solution of 10 parts of chromic acid in 400 parts of water is then run in gradually at waterbath temperature, and the whole is heated on the waterbath for several hours The dyestufi after being filtered ofi' b suction and washed until neutral, is then oiled with dilute hypochlorite solution, until the shade, as determined by means of a test portion, is no longer altered. The resulting dyestufi gives handsome, brown, very fast dyeinigs on cotton from a dark blue vat. The so ution of the dyestufi in sulfuric acid is violet with a reddish tinge. We think it probable that the oxidation proceeds in accordance with the following equation:

. Example 4 i rich brown. The reaction proceeds probably as indicated in Example 3.

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Example 5 10 parts of amino-Bz-1-brombenzanthrone corresponding probably to the formula:

4 Br which is obtainable by brominating the acetyl derivative of the aforesaid amino-benzanthrone in glacial acetic acid and saponifying the acetyl compound thus obtained, are introduced into a melt consisting of parts of caustic potash and 50 parts of ethyl alcohol at a temperature of 140 to 145 C., this temperature being maintained for a further hour after all has been added. The melt is then stirred into water, and the dyestuffs precipitated by blowing filtered off by suction, and dried. The dyestuif thus obtained gives a violet solution in sulfuric acid, and dyes cotton full green shades from the blue vat. The green shade turns brown on treatment with chlorine. The dyestuff is identical with that obtained according to Example 1.

Ewample 6 l0 parts of acetylamino-benzanthrone-Bz- 'l-thiocresylether obtainable by condensing acetylamino-Bz-l-brombenzant one (which ma be obtained according to Example 5) wit p-thiocresol, are introduced into a melt of 50 parts of caustic potash and 50 parts of ethyl alcohol and'further treated as in Example 5. The dyestufi thus obtained is identical with that produced according to Example 5.

Emarmple '7 10'parts of amino-Bz-1-benzanthrone-mercapto-methyl-ether, obtainable by methylating the sodium compound of amino-Bz-l-benzanthrone-mercaptan, which is obtained as a by-product by the reduction of the aforesaid nitrobenzanthrone with sodium sulfid, are treated as described in Example 5. The d estufi thus produced is identical with t at obtained according to the said example.

Example 8 10 arts of the nitrobenzanthrone correspondmg probably to the formula:

obtainable according to Example 2 of the said 'U. S. Patent No. 876,679 are introduced into a melt of alcoholic potash, pre ared by heating 50 parts of potassium hy roxid with 50 parts of ethyl alcohol. The temperature is maintained at C. for half an hour, and is then gradually raised to 0., the alcohol thereby distilling 0E, and the melt is kept at that temperature until the forma- I tion of the dyestufl' is completed. When cold, the melt is brought into water, blown with air in order to precipitate the dyestuff which is then filtered oil and dried. The resulting dyestuff dissolves to a red-violet solution in concentrated sulfuric acid and gives fast brown dyeings on cotton from the blue vat. A dyestuff of purer shade is obtained by boiling up the crude dyestuff with hypochlorite. The dyeings furnished by this product change into a reddish orange when chlorinated on the fibre.

What we claim is:

1. The process of producing new valuable vat dyestuffs, which consists in treating a substance selected from the group consist ing of aminoben'zanthrone, obtainable by reducing the nitrobenzanthrone which can be obtained by treating benzanthrone with nitric acid in boiling glacial'acetic acid, the substitution products thereof, which contain an a exchangeable substituent in the Bz-l-position, and the N-acyl derivatives thereof, with caustic alkali.

2. The process of producing a new valuable vat dyestuff which consists in treating a substance selected from the group consisting of aminobenzanthrone, obtainable by reducing the nitrobenzanthrone which can be obtained by treating benzanthrone with nitric acid in A boiling glacial acetic acid, the substitution products thereof, which contain an exchangeable substituent in the Bz-l-position, and the N-acyl, derivatives thereof, in an alcoholic caustic potash melt at temperature of from 120 to 200 C.

In testimony whereof we have hereunto set our hands.

PAUL NAWIASKY. f MULLER. 

